The present invention relates to a multi-point fuel injector for use in a combustor of a gas turbine engine or other types of combustors.
One of the biggest challenges for gas turbines, especially for industrial applications, is to have good emission performance and combustion stability for a wide range of power settings and ambient condition. If one has an industrial gas turbine with low emissions of NOx, CO and UHC at 100% power, as one reduces the power, which is usually done by reducing the amount of fuel to the engine, the fuel/air mixture in the combustor typically gets leaner. The leaner mixture of fuel/air lowers the flame temperature and creates a flame which can be quenched relatively easily by a cooler combustor wall or cooling film on the combustor wall. The quenching effect creates excessive CO and UHC and high dynamic pressure. If they are not further oxidized, the CO and UHC become pollutants. The other issue associated with too lean fuel/air mixture is that it creates unstable combustion. Conversely, if one has a gas turbine with low NOx, CO, UHC and acoustics at part power condition, as one increases the power, which is usually done by increasing the amount of fuel to the engine, the fuel/air mixture in the combustor typically gets richer. The richer mixture of fuel/air raises the flame temperature and creates a flame which can generate more NOx. Similar situations can happen with different ambient temperatures. If one has a gas turbine with low NOx, CO, UHC and acoustics at high ambient temperature, as ambient temperature becomes lower, the flame temperature decreases which may create high CO, UHC and unstable flame. Or if one has a gas turbine with low NOx, CO, UHC and acoustics at low ambient temperature, as ambient temperature becomes higher, the flame temperature increases which may create excessive NOx.